Abstract: Phenytoin is widely used against all types of partial and tonic-clonic seizures. Phenytoin may alter the release and action of different hormones which may contribute to sexual dysfunction. The present study is aimed at the effect of phenytoin induced differential regulation of LPL gene in albino rat testis. The albino rats were divided into two groups, control and test. The test group was given 150mgs/kg/body weight of phenytoin orally and equal amount of normal saline was given for the control group. After 45 days with the rat under deep anesthesia, the testis were removed from the scrotum and stored in liquid nitrogen. The stored specimens of testis of control and tests group were subjected to cDNA microarray analysis. This study showed the differential expression of gene LPL in test group when compared with the control group.